308 lines
9.5 KiB
Python
308 lines
9.5 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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"""
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AT客户端模块
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负责4G模块的AT命令通信和URC解析
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"""
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import _thread
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from maix import time
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import re
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import threading
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class ATClient:
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"""
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单读者 AT/URC 客户端：唯一读取 uart4g，避免 tcp_main/at()/OTA 抢读导致 EOF / 丢包。
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- send(cmd, expect, timeout_ms) : 发送 AT 并等待 expect
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- pop_tcp_payload() : 获取 +MIPURC:"rtcp" 的 payload（已按长度裁剪）
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- pop_http_event() : 获取 +MHTTPURC 事件（header/content）
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"""
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def __init__(self, uart_obj):
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self.uart = uart_obj
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self._cmd_lock = threading.Lock()
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self._q_lock = threading.Lock()
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self._rx = b""
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self._tcp_payloads = []
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self._http_events = []
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# 当前命令等待状态（仅允许单命令 in-flight）
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self._waiting = False
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self._expect = b"OK"
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self._resp = b""
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self._running = False
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def start(self):
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if self._running:
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return
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self._running = True
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_thread.start_new_thread(self._reader_loop, ())
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def stop(self):
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self._running = False
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def flush(self):
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"""清空内部缓存与队列（用于 OTA/异常恢复）"""
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with self._q_lock:
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self._rx = b""
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self._tcp_payloads.clear()
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self._http_events.clear()
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self._resp = b""
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def pop_tcp_payload(self):
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with self._q_lock:
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if self._tcp_payloads:
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return self._tcp_payloads.pop(0)
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return None
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def pop_http_event(self):
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with self._q_lock:
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if self._http_events:
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return self._http_events.pop(0)
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return None
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def _push_tcp_payload(self, payload: bytes):
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# 注意：在 _reader_loop 内部解析 URC 时已经持有 _q_lock，
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# 这里不要再次 acquire（锁不可重入，会死锁）。
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self._tcp_payloads.append(payload)
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def _push_http_event(self, ev):
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# 同上：避免在 _reader_loop 持锁期间二次 acquire
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self._http_events.append(ev)
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def send(self, cmd: str, expect: str = "OK", timeout_ms: int = 2000):
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"""
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发送 AT 命令并等待 expect（子串匹配）。
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注意：expect=">" 用于等待 prompt。
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"""
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expect_b = expect.encode() if isinstance(expect, str) else expect
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with self._cmd_lock:
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# 初始化等待
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self._waiting = True
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self._expect = expect_b
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self._resp = b""
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# 发送
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if cmd:
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# 注意：这里不要再用 uart4g_lock（否则外层已经持锁时会死锁）。
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# 写入由 _cmd_lock 串行化即可。
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self.uart.write((cmd + "\r\n").encode())
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t0 = time.ticks_ms()
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while time.ticks_ms() - t0 < timeout_ms:
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if (not self._waiting) or (self._expect in self._resp):
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self._waiting = False
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break
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time.sleep_ms(5)
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# 超时也返回已收集内容（便于诊断）
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self._waiting = False
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try:
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return self._resp.decode(errors="ignore")
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except:
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return str(self._resp)
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def _find_urc_tag(self, tag: bytes):
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"""
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只在"真正的 URC 边界"查找 tag，避免误命中 HTTP payload 内容。
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规则：tag 必须出现在 buffer 开头，或紧跟在 b"\\r\\n" 后面。
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"""
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try:
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i = 0
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rx = self._rx
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while True:
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j = rx.find(tag, i)
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if j < 0:
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return -1
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if j == 0:
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return 0
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if j >= 2 and rx[j - 2:j] == b"\r\n":
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return j
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i = j + 1
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except:
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return -1
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def _parse_mipurc_rtcp(self):
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"""
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解析：+MIPURC: "rtcp",<link_id>,<len>,<payload...>
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之前硬编码 link_id=0 会导致在多连接/重连场景下收不到数据。
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"""
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prefix = b'+MIPURC: "rtcp",'
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i = self._find_urc_tag(prefix)
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if i < 0:
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return False
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# 丢掉前置噪声
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if i > 0:
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self._rx = self._rx[i:]
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i = 0
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j = len(prefix)
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# 解析 link_id
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k = j
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while k < len(self._rx) and 48 <= self._rx[k] <= 57:
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k += 1
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if k == j or k >= len(self._rx):
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return False
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if self._rx[k:k+1] != b",":
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self._rx = self._rx[1:]
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return True
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try:
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link_id = int(self._rx[j:k].decode())
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except:
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self._rx = self._rx[1:]
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return True
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# 解析 len
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j2 = k + 1
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k2 = j2
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while k2 < len(self._rx) and 48 <= self._rx[k2] <= 57:
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k2 += 1
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if k2 == j2 or k2 >= len(self._rx):
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return False
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if self._rx[k2:k2+1] != b",":
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self._rx = self._rx[1:]
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return True
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try:
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n = int(self._rx[j2:k2].decode())
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except:
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self._rx = self._rx[1:]
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return True
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payload_start = k2 + 1
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payload_end = payload_start + n
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if len(self._rx) < payload_end:
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return False # payload 未收齐
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payload = self._rx[payload_start:payload_end]
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# 把 link_id 一起带上，便于上层过滤（如果需要）
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self._push_tcp_payload((link_id, payload))
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self._rx = self._rx[payload_end:]
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return True
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def _parse_mhttpurc_header(self):
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tag = b'+MHTTPURC: "header",'
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i = self._find_urc_tag(tag)
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if i < 0:
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return False
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if i > 0:
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self._rx = self._rx[i:]
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i = 0
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# header: +MHTTPURC: "header",<id>,<code>,<hdr_len>,<hdr_text...>
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j = len(tag)
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comma_count = 0
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k = j
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while k < len(self._rx) and comma_count < 3:
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if self._rx[k:k+1] == b",":
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comma_count += 1
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k += 1
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if comma_count < 3:
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return False
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prefix = self._rx[:k]
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m = re.search(rb'\+MHTTPURC: "header",\s*(\d+),\s*(\d+),\s*(\d+),', prefix)
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if not m:
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self._rx = self._rx[1:]
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return True
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urc_id = int(m.group(1))
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code = int(m.group(2))
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hdr_len = int(m.group(3))
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text_start = k
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text_end = text_start + hdr_len
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if len(self._rx) < text_end:
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return False
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hdr_text = self._rx[text_start:text_end].decode("utf-8", "ignore")
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self._push_http_event(("header", urc_id, code, hdr_text))
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self._rx = self._rx[text_end:]
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return True
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def _parse_mhttpurc_content(self):
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tag = b'+MHTTPURC: "content",'
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i = self._find_urc_tag(tag)
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if i < 0:
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return False
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if i > 0:
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self._rx = self._rx[i:]
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i = 0
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# content: +MHTTPURC: "content",<id>,<total>,<sum>,<cur>,<payload...>
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j = len(tag)
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comma_count = 0
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k = j
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while k < len(self._rx) and comma_count < 4:
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if self._rx[k:k+1] == b",":
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comma_count += 1
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k += 1
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if comma_count < 4:
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return False
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prefix = self._rx[:k]
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m = re.search(rb'\+MHTTPURC: "content",\s*(\d+),\s*(\d+),\s*(\d+),\s*(\d+),', prefix)
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if not m:
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self._rx = self._rx[1:]
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return True
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urc_id = int(m.group(1))
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total_len = int(m.group(2))
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sum_len = int(m.group(3))
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cur_len = int(m.group(4))
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payload_start = k
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payload_end = payload_start + cur_len
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if len(self._rx) < payload_end:
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return False
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payload = self._rx[payload_start:payload_end]
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self._push_http_event(("content", urc_id, total_len, sum_len, cur_len, payload))
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self._rx = self._rx[payload_end:]
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return True
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def _reader_loop(self):
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while self._running:
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# 关键：UART 驱动偶发 read failed，必须兜住，否则线程挂了 OTA/TCP 都会卡死
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try:
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d = self.uart.read(4096) # 8192 在一些驱动上更容易触发 read failed
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except Exception as e:
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try:
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print("[ATClient] uart read failed:", e)
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except:
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pass
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time.sleep_ms(50)
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continue
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if not d:
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time.sleep_ms(1)
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continue
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with self._q_lock:
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self._rx += d
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if self._waiting:
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self._resp += d
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while True:
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progressed = (
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self._parse_mipurc_rtcp()
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or self._parse_mhttpurc_header()
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or self._parse_mhttpurc_content()
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)
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if not progressed:
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break
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# 使用 ota_manager 访问 ota_in_progress
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try:
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from ota_manager import ota_manager
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ota_flag = ota_manager.ota_in_progress
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except:
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ota_flag = False
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has_http_hint = (b"+MHTTP" in self._rx) or (b"+MHTTPURC" in self._rx)
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if ota_flag or has_http_hint:
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if len(self._rx) > 512 * 1024:
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self._rx = self._rx[-256 * 1024:]
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else:
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if len(self._rx) > 16384:
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self._rx = self._rx[-4096:]
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